The present invention relates generally to footwear, and more particularly to a shoe sole which is provided with retractable cleats.
There are known various types of traction-improving devices having spikes or cleats which may be attached to shoes and boots for giving the wearer surer footing. There are also known devices in which provision is made in a shoe or boot sole for mounting a set of spikes or pins which are linked mechanically to a mechanism by operation of which the spikes can be made to protrude outwardly from the sole bottom or to be retracted into the sole proper. Examples of known retractable spike arrangements as applied to shoe soles can be found from U.S. Pat. Nos. 3,793,751 and 4,375,729. In the former, a cam mechanism is utilized, with a pair of long cams being operated to depress spike plates so that the spikes project downwardly from the sole bottom. A manual knob at the rear of the heel operates a heel cam directly and a sole cam via a flexible coupling shaft. Such an arrangement is useful for a golf shoe where manual operation of the cam mechanism need be performed only upon commencing and finishing a round of golf, that is, upon entering on and leaving from the golf course; however, such an arrangement does not lend itself to frequent use in winter ice and snow because of the need to operate the manual control knob at the heel, which presents problems of access and operation upon encountering, for example, snow or slush of several inches' depth.
The latter arrangement also utilizes a cam member for urging spikes from a retracted to an extending position. A cam actuating mechanism in the form of a sliding member can be operated by finger pressure applied against a thin-walled heel portion of the shoe. However, while such an arrangement avoids the access problems inherent with protuding manual knobs, it still requires the wearer to operate the mechanism directly at the heel, which is difficult and requires stooping, bending down or sitting to reach both heels every time it is desired to extend or retract the spikes.
Such prior arrangements thus present disadvantages in use for persons who must frequently walk across patches of slippery ice or snow and who also must frequently enter and exit buildings, for example delivery persons and letter carriers and whose hands are frequently laden with goods or mail. For example, when a delivery person wearing the conventional type retractable spike shoes is making a delivery to a building, home or office during icy winter weather conditions, it might be necessary for the delivery person to first manually operate the mechanism in each shoe to extend the spikes before alighting from the delivery vehicle, then make their way across icy ground to the building entrance, whereupon, before entering, it would then be necessary to once more manually operate the mechanism in each shoe to retract the spikes to avoid damage to the floor covering in the building, and then, after making the delivery or pickup to once more extend the spikes upon exiting, make their way to the vehicle, retract the spikes, and so on.
It is desirable therefore to improve on the known retractable spike type footwear in order to eliminate the requirement of reaching down to each shoe every time the spikes are to be extended or retracted, which is an encumbrance to the utility of such footwear.
It is therefore an object of the present invention to overcome the above-noted disadvantages by providing a shoe sole with retractable cleats which does not require the wearer to manually operate the individual extending/retracting mechanism at each shoe.
It is another object of the present invention to provide a shoe sole with retractable cleats which does not depend upon mechanical linkages for extending and retracting the cleats.
It is further an object of the present invention to provide a shoe sole with retractable cleats which includes a remotely-operated actuating means which permits the wearer to conveniently actuate extension/retraction of the cleats of both shoe soles simultaneously by remote control using only one hand and without stooping down.
These and other advantages and objects are realized in the present invention by providing a shoe sole which includes pneumatic or hydraulic chambers provided therein. Each chamber is provided with a cleat plate which is vertically displaceable under the influence of pneumatic or hydraulic pressure, the cleat plates thus acting as pistons within the chambers. Springs provided between the bottom of each chamber and the cleat plates urge the cleat plates upwardly to a normal retracted position in which the cleats do not protrude from the sole bottom. Pressure tubing connects the chambers to a remotely located pump by which pneumatic or hydraulic pressure can be supplied to the space above the cleat plate in each chamber to force the cleat plate downwardly against the springs to an extended position with the cleats protruding from the sole bottom, and to maintain pressure in the chambers to keep the cleats extended.
The pump in a preferred embodiment of the invention is a remotely connected squeeze bulb type air pump provided with a valve whereby, before pumping air into the chambers to extend the cleat plates against the force of the springs, the valve is closed to communicate pneumatic pressure to the chambers, and then the pump is operated to extend the cleats, and the pressure in the chambers keep the cleats extended. Opening the valve bleeds off the air from the chambers, causing the cleats to retract under the urging of the springs. In this way, the operation of extending the cleats merely requires a simple manual operation of the valve and squeezing of the pump bulb, and retraction of the cleats is performed by simply opening the valve.
Advantageously, plural chambers can be provided in each of a pair of shoe soles according to the present invention, and the separate chambers can be connected to a mutual pressure supply line. As a further advantage, it is possible in accordance with the present invention, to utilize a single pressure source for simultaneously actuating the cleats in both soles of a pair of shoes so equipped by connecting pressure lines from the chambers in each sole to a single pump. By the use of pressure lines for intercommunication between the pressure source and chambers in both soles, it is thereby made possible to locate the pressure source remotely at a desired distance from the shoe soles and at a convenient location on the wearer's person, for example, at the waist, so as to be within easy reach.
It is possible to retract cleats by a vacum system type (air or hydraulic) pump, which would eliminate the use of springs.